It is common within the automobile industry to use glass fiber wools in the production of molded automotive insulation products, e.g. topliners. Glass fiber wools are typically made by first impregnating glass fibers with a thermosetting binder, such as a phenolic resin, and thereafter consolidating the glass fibers and thermosetting binder into a loosely packed mass. This mass is then passed to an oven where the bonded glass fibers are compressed to a selected thickness and density and then cured at a relatively high temperature, e.g. 550.degree. F.
Automotive insulation products fashioned from these glass fiber wools and the process for producing these wools and insulation products are not without drawbacks and limitations, however.
To begin with, the glass fiber has a tendency to be too rigid for many potential applications because of the brittleness imparted to the fiber by the thermosetting, e.g. phenolic, resin binder. Furthermore, the glass fibers are not always strong enough for various end uses such as hoodliners, van converter door panels, and package trays.
Because of the thermosetting binder, high mold temperatures and specialized aluminum molds must be employed. And because high temperature molds must be used, low melting point materials cannot be laminated onto the glass fibers during the initial molding process. Thus, if lamination is to occur the molded fiber must be cooled down considerably beforehand.
While other materials have been available such as modified glass fiber mats and non-woven textiles, their uses have not been without limitations either.
For example, U.S. Pat. No. 4,596,737 discloses a glass fiber mat containing a heat curable, thermosetting binder. Additionally, the mat is impregnated with a latex resin to impart a degree of flexibility to the mat. While the disclosed mat has some degree of flexibility, it can still have too much rigidity and too low of strength for various end uses as automotive insulation. Furthermore, the foregoing disclosed limitations associated with lamination would still be present.
U.S. Pat. No. 4,673,616 discloses a moldable latex impregnated textile material composed of organic fibers needled into a non-woven web of sheet. The latex impregnant contains a filler and a stiffener such as styrene-butadiene. The use of only organic fibers in the mat, however, presents a temperature stability problem at temperatures of around 200.degree. F. or higher as there will be a tendency of the mat to droop during molding.
What is needed in the industry is a fibrous mat product which has sufficient strength and temperature stability and which is flexible yet rigid enough to find a variety of end uses as insulation and the like within the automotive and other industries. What is also needed is a process for making molded fibrous insulation products which avoids the difficulties and limitations possessed by the conventional process.